1968 - Two change• Grooves removed from the Receiver (now smooth flattop receiver). (Mar 1968 - Feb 1978)• Curved bolt handle now welded to bolt.
1972 - Two changes• Stamped Serial numbers introduced ( 000001 - 025650). (Apr 1972)• Hole in bolt handle made shallow (1972–1974)
1975 - One change. Serial numbers ( 100780 - 141460)• Hole in bolt handle eliminated.